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Let alpha, beta be such that pi lt alpha...

Let `alpha, beta` be such that `pi lt alpha- beta lt 3pi`. If `sin alpha+ Sin beta=(-21)/(65) and cos alpha+ Cos beta=(-27)/(65)` then the value of `"cos" (alpha- beta)/(2)` is

A

`(-3)/(sqrt(130))`

B

`(-6)/(65)`

C

`(6)/(65)`

D

`(3)/(sqrt(130))`

Text Solution

Verified by Experts

The correct Answer is:
A
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